Identification of the in vitro N-oxidized metabolites of (+)- and (-)-N-benzylamphetamine.

This study has identified (+)- and (-)-N-benzyl-N-hydroxyamphetamine as metabolites after incubation of both (+)- and (-)-N-benzylamphetamine with fortified rabbit liver homogenates. The isomeric hydroxylamine metabolites were identified using the techniques of g.l.c., t.l.c. and combined g.l.c.-mass spectrometry (ms) and by comparison with results from reference samples. An additional novel metabolic product was identified after incubation of N-benzylamphetamine which had properties consistent with that of N-benzyl-amphetamine nitrone.     

The preparation and properties of (+)- and (−)-guanoxan

(±)-2-Aminomethyl-1, 4-benzodioxan has been resolved into its optically active isomers: (+)- and (-)-guanoxan have been synthesized from these. The pharmacological effects of racemic-guanoxan and of the two optical isomers have been compared on the isolated central ear artery of the rabbit, on the pithed rat in which pressor responses were evoked by stimulation of the thoraco-lumbar sympathetic outflow, and on the pre- and post-ganglionically stimulated nictitating membrane of the cat. The two isomers were equipotent in producing adrenergic neuron blockade. Initial catecholamine release was weak in the cat, but occurred more powerfully in the rabbit ear artery and in the rat. Ability to produce this effect resided mainly with the (+)-isomer. α-Adrenoreceptor blocking activity was detectable in the rat and was produced mainly by the (+)-isomer suggesting that its stereochemical configuration corresponds to that of D-(-)-noradrenaline. Ganglion blockade was an unimportant action of the compounds, but both isomers possessed weak atropine-like activity in the rat.     

Oral Cavity Absorption of (R)−8−Hydroxy−2−(di-n-propylamino)tetralin and (S)−8−Acetyl−2−(di-n-propylamino)tetralin in the Rat

The present communication reports on the efficacy of (R)?8?OH-DPAT ((R)?8?hydroxy?2?(di-n-propylamino)tetralin) and (S)-LY?41 ((S)?8?acetyl?2?(di-n-propylamino)tetralin) in displaying the 5?HT_1A syndrome and decreasing body temperature after administration of the compound subcutaneously into the gastric ventricle or into the oral cavity in the rat. The dose range eliciting a clear-cut 5?HT_1A syndrome and hypothermia after oral cavity administration was 1/10-1/30 that of the gastric ventricle dose range, but 10?30 times higher than the dose range used for subcutaneous administration of both (R)?8?OH-DPAT and (S)-LY?41. Determination of the concentrations of (R)?8?OH-DPAT in plasma and brain tissue confirmed a higher bioavailability after oral cavity than after gastric ventricle administration; plasma and brain tissue concentrations of the drug were found to be approximately 3 times those after 10 μmol kg^?1 orally than after 100 μmol kg^?1 gastroventrically at 15?60 min after administration of (R)?8?OH-DPAT. These findings suggest that the oral cavity may be an important site for drug delivery of 8?OH-DPAT, LY?41 and other compounds with a low gastrointestinal bioavailability.     

Metabolism of clebopride in vitro Identification of N-oxidized products

1. N-(1′-Benzyl-4′-piperidyl-N-oxide)-4-amino-5-chloro-2-methoxybenzamide,N-(4′-(N-hydroxylpiperidyl))-4-amino-5-chloro-2-methoxybenzamide and N-(4′-(Δ1′-piperidyl-N-oxide))-4-amino-5-chloro-2-methoxybenzamide were obtained from chloro- form extracts of incubation mixtures of clebopride or desbenzyl clebopride with 9000g supernatant of liver homogenates of male NZW rabbits.

2. These metabolites were identified using electron impact (low and high resolution) and field desorption mass spectrometry, and computer averaged time proton magnetic resonance spectroscopy.     

Syntheses of (RS)- and (S)-(−)-Nazlinin and (RS)- and (+)-6-Azacyclodeca[5,4-b]indol-1-amine

(RS)-1-(4-Aminobutyl)-1,2,3,4-tetrahydro-β-carboline ((RS)-1) was synthesized in two different ways. The preparation of (S)-(?)-1 was performed both by asymmetric reduction with ? 95% ee and by synthesis from (S)-(+)-3. From this compound also (+)-6-azacyclodeca[5,4-b]indol-1-amine ((+)-2) was prepared with high enantioselectivity.     

Metabolism of promethazine in vitro. Identification of N-oxidized products

1. Incubation of promethazine (Ia) and desmethylpromethazine (Ib) with 9000g supernatant fractions of rabbit liver homogenate resulted in formation of N-dealkylated, N-oxygenated and ring-hydroxylated products.

2. The N-oxidation products identified by t.l.c. and mass spectra using synthetic reference products are promethazine-N-oxide (IX) and the nitrone (VIII), which is believed to be formed chemically and metabolically from the metabolite N-hydroxydesmethylpromethazine (VII).     

−(−)Gossypol promotes the apoptosis of bladder cancer cells in vitro

Dysregulation of Bcl2 family member proteins has been associated with poor chemotherapeutic response in bladder cancer, suggesting that agents targeting these crucial proteins may provide an interventional strategy to slow or halt bladder cancer progression and metastasis. In this study, we investigated whether the cottonseed polyphenol, -(-)gossypol, a BH3 mimetic, can reduce the expression of pro-survival, or increase the expression of pro-apoptotic, Bcl2 family proteins and thereby effectively sensitize otherwise resistant bladder cancer cells to the standard chemotherapeutic drugs gemcitabine, paclitaxel and carboplatin. These studies show that gossypol induced apoptosis in both chemosensitive UM-UC2 and chemoresistant resistant UM-UC9 bladder cancer cells in vitro in a dose and time dependent manner via a caspase mediated death signaling pathway. Moreover, in combined treatments, gossypol synergized with gemcitabine and carboplatin to induce apoptosis in chemoresistant bladder cancer cells. This effect was associated with the down-regulation the Bcl-xl and Mcl-1 pro-survival Bcl2 family proteins and up-regulation of the Bim and Puma BH3-only Bcl2 family proteins. Overall, these studies show that gossypol sensitizes bladder cancer cells to standard chemotherapeutic drugs and may provide a promising new strategy for bladder cancer treatment.     

Optical isomerization of R(−)-clidanac to the biologically active S(+)-isomer in guinea-pigs

Optical isomerization of clidanac (RS-6-chloro-5-cyclohexyl-1-indancarboxylic acid, I), an anti-inflammatory drug having a chiral centre in its molecule, was evaluated in guinea-pigs. After oral administration of R(?)-I, the biologically active S(+)-isomer was detectable in the plasma, in the early stages. At 3 h after dosing R(?)-I, the plasma contained above 90% of the S(+)-isomer. Little conversion of S(+)-I to R(?)-I was observed. This may account for the equivalent in vivo activities of R(?)- and S(+)-I in this species. Determination of the enantiomeric composition required derivatization of the enantiomers to their diastereomeric amides after which thin layer chromatography (t.l.c.) was used for the separation. The quantitative determination of the compounds so-separated was accomplished by in situ measurements of the u.v.-reflectance. The t.l.c.-u.v.-densitometric procedure was also used to determine the plasma concentration of I.     

Enzymatic Synthesis of (S-(−)-3-(3,4-Dihydroxyphenyl)lactic Acid

The first enzymatic synthesis of (S)-(?)-3-(3,4-dihydroxyphenyl)lactic acid, a DOPA metabolite and naturally occurring compound with a broad spectrum of pharmacological activities, is described. L-Hydroxyisocaproate dehydrogenase was used as enzyme.     

Synthesen in der Isocamphanreihe, 6. Mitt. (+)- und (−)-Isocamphenilansäure

Syntheses in the Isocamphane Series, VI: (+)- and (?)-Isocamphenilanic Acid The optically active isomers of isocamphenilanic acid (3) were prepared by fractional crystallization of the dehydroabietylamine salt of 3. The optical purity was proved by thermal analysis. A melting point diagramme is presented.     

Labeling in vivo of sigma receptors in mouse brain with [3H]-(+)-SKF 10,047: Effects of phencyclidine, (+)- and (−)-N-allylnormetazocine,and other drugs

The sigma receptor, so named because of the distinct pharmacolgical profile produced by its prototypic agonist SKF 10,047 (N-allynormetazocine), is believed to mediate mania and psychotomimetic effects in man. While this sigma receptor has received extensive biochemical and pharmacological characterization in vitro, little information is available on the nature of the sigma site in vivo. In the present study, we examined the binding of [³H]-(+)-SKF 10,047 to sigma receptors in mouse brain in vivo and to sigma receptors in mouse and guinea pig brain in vitro and determined the relative potencies of various drugs in displacing this ligand. Mice were injected with 5 μCi of [³H]-(+)-SKF 10,047 into the tail vein. After various time intervals, the mice were decapitated; their brains were rapidly removed, weighed, and homogenized in 50 mM Tris-HCI buffer, pH 7.7; and total and particulate bound radioactivity were determined. Specifically bound [³H]-(+)-SKF 10,047 in the particulate fraction was defined as the difference in total radioactivity in the particulate fraction obtained from vehicle-injected mice minus the radioactivity in the particulate fraction from haloperidol (2 mg/kg i.p.)-injected mice. Specifically bound [³H]-(+)-SKF 10,047 in the particulate fraction reached peak levels of 30 min after i.v. injection and constituted 90–95% of the total particulate radioactivity. Labeling of the sigma sites could be blocked in vivo by injecting mice i.p. with the drug 30 min before the i.v. injection of the ³H-ligand. Under these conditions, (+)-SKF 10,047, (+)-3-PPP, cyclazocine, pentazocine, and haloperidol were found to be the most potent compounds in reducing specific [³H]-(+)-SKF 10,047 binding. Neuroleptics such as thioridazine and chlorpromazine had good potency, while clozapine, spiperone, and sulpiride were very weak inhibitors in vivo. Specific [³H]-(+)-SKF 10,047 binding was also reduced in vivo by imipramine, dl-propranolol, bupropion, rimcazole, and phenoxybenzamine, but was not reduced by apomorphine and naloxone at doses of 50 mg/kg i.p. Phencyclidine, m-NH₂-PCP and (?)-3-PPP were only weak inhibitors of (+)-SKF 10,047 binding in vivo. The relative potencies of these agents obtained in vivo correspond well with their relative affinities obtained in vitro in mouse and guinea pig brain for displacing [³H]-(+)-SKF 10,047 but not with their relative affinities for displacing TCP in guinea pig brain. Comparison of the dose-response curves for the drug revealed the presence of perhaps two sites labeled by [³H]-(+)-SKF 10,047 in vivo.     

Identification of the major urinary metabolites of (+)-catechin and 3-O-methyl-(+)-catechin in man

Following oral administration of (+)-catechin and 3-O-methyl-(+)-catechin to human volunteers the major urinary metabolites were shown to be the glucuronides of 3'-O-methyl-(+)-catechin respectively. Isolations from urine and from synthetic products have been carried out by semi-preparative high performance liquid chromatography; definitive elucidations of structures have been carried out by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy.     

Myricetin, quercetin, (+)-catechin and (−)-epicatechin protect against N-nitrosamines-induced DNA damage in human hepatoma cells

The aim of this study was to investigate the protective effect of myricetin, quercetin, (+)-catechin and (−)-epicatechin, against N-nitrosodibutylamine (NDBA) and N-nitrosopiperidine (NPIP)-induced DNA damage in human hepatoma cells (HepG2). DNA damage (strand breaks and oxidized purines/pyrimidines) was evaluated by the alkaline single-cell gel electrophoresis or Comet assay. (+)-Catechin at the lowest concentration (10 μM) showed the maximum reduction of DNA strand breaks (23%), the formation of endonuclease III (Endo III, 19–21%) and formamidopyrimidine-DNA glycosylase (Fpg, 28–40%) sensitive sites induced by NDBA or NPIP. (−)-Epicatechin also decreased DNA strand breaks (10 μM, 20%) and the oxidized pyrimidines/purines (33–39%) induced by NDBA or NPIP, respectively. DNA strand breaks induced by NDBA or NPIP were weakly reduced by myricetin at the lowest concentration (0.1 μM, 10–19%, respectively). Myricetin also reduced the oxidized purines (0.1 μM, 17%) and pyrimidines (0.1 μM, 15%) induced by NDBA, but not the oxidized pyrimidines induced by NPIP. Quercetin did not protect against NDBA-induced DNA damage, but it reduced the formation of Endo III and Fpg sensitive sites induced by NPIP (0.1 μM, 17–20%, respectively). In conclusion, our results indicate that (+)-catechin and (−)-epicatechin at the concentrations tested protect human derived cells against oxidative DNA damage effects of NDBA and NPIP. However, myricetin at the concentrations tested only protects human cells against oxidative DNA damage induced by NDBA and quercetin against oxidative DNA damage induced by NPIP.